For many hearing loss patients, bone conduction hearing aids offer a better solution than more conventional acoustic/air transmitting hearing aids. Indeed, for some patients bone conduction hearing aids offer the only solution. Bone conduction hearing assistance generally involves vibration of the patient's mastoid bone to improve hearing perception. In a typical bone conduction hearing aid, sound sensed by a microphone is converted to an electrical signal and amplified. The amplified signal is then received by a small vibrator which vibrates the mastoid bone. Strategic placement of the vibrator on the user is essential in order to achieve optimal results. For example, some bone conduction hearing aids teach that the vibrator should be placed against the skin behind the ear, while others teach placing the vibrator on the forehead. Still others teach surgical implantation of the vibrator directly into the mastoid bone for better transmission of vibration. However, all of these approaches have significant disadvantages.
One particularly effective approach has been to mount the vibrator on an in-the-ear structural member. The structural member is inserted in the patient's ear canal so that the vibrator is positioned adjacent the mastoid bone. While this approach has been shown to provide excellent vibration transfer characteristics, it is unavailable for patients with ear canals too small to receive the vibrator, such as patients who suffer from congenital atresia—a condition where the ear canal is narrowed or, in some cases, entirely closed off from the ear drum.
Therefore, there is a need for an improved bone conduction hearing aid for hearing loss patients with limited treatment options.